Circular electrical connector

ABSTRACT

An electrical connector includes a hollow conductive post member having a circular periphery, a foot portion and a distal end. The distal end has a generally cup shaped indentation. A base member is included having top and bottom surfaces. The foot portion of the post member is mounted to the top surface. At least one standoff extends from the bottom surface of the base member. The at least one standoff is for resting against a contact surface when soldering the electrical connector to the contact surface, thereby separating the bottom surface from the contact surface to define a minimum volume therebetween for occupation by solder.

RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application Ser. No.10/445,741, filed May 27, 2003, which is a divisional of U.S.application Ser. No. 10/209,556, filed Jul. 30, 2002, now U.S. Pat. No.6,599,157, issued Jul. 29, 2003, which is a divisional of applicationSer. No. 09/847,861, filed May 2, 2001, now U.S. Pat. No. 6,475,043,issued Nov. 5, 2002, which is a continuation-in-part of application Ser.No. 09/491,135, filed Jan. 26, 2000, now U.S. Pat. No. 6,249,966, issuedJun. 26, 2001, which is a continuation of application Ser. No.09/199,810, filed Nov. 25, 1998, now U.S. Pat. No. 6,039,616, issuedMar. 21, 2000. The entire teachings of the above applications andpatents are incorporated herein by reference.

BACKGROUND

[0002] A variety of electrical connectors have been proposed in the pastfor numerous specific purposes. For example, electrical connectors havebeen proposed for use in glass, e.g., vehicle windscreens, for allowingelectrical connection between electrical devices embedded in the glassand sources of power and/or other electrical devices. Windscreens oftenare equipped with electric heaters or defrosters which are embeddedbetween layers which make up the windscreen, and include a simple flatelectrical contact for establishing an electrical connection with thedefroster. Such flat connections are typically formed by screening aconductive coating, e.g., silver, onto an exterior portion of thewindscreen in which a lead from the defroster protrudes. Thus, in orderto make electrical contact with the defroster, an electrical connectormust be mounted onto the glass so that the connector establisheselectrical communication with the flat conductive coating.

[0003] One electrical connector which has been proposed for mounting ona conductive coating of a windscreen includes an upstanding cylindricalpost and a flat base which carries a layer of solder thereon. Such anelectrical connector was first made available by Antaya, Inc., Cranston,R.I. The layer of solder is pressed against the contact on thewindscreen, and the solder is heated to flow the solder. Pressure issimultaneously applied to the connector, which presses against thewindscreen's contact. While this device has in the past proven to beuseful and has advantages in certain applications, because this priorconnector has a flat surface which is soldered against the flat surfaceof a windscreen's contact, the pressure applied when soldering tends topress or squeeze much of the solder out from under the connector. Thus,the prior connector is oftentimes mismounted to the windscreen, becausemost of the solder has been squeezed out from between the connector andthe windscreen's contact during the soldering process. This results inconnectors which cannot meet vehicle manufacturing standards for thestrength of the connections between windscreens and their electricalconnectors. Such mismounting of the prior electrical connectors resultsin a considerable amount of rework, scrap, and increases in labor timeand costs to correct mismounted connectors.

[0004] A further difficulty encountered with prior electrical connectorsis that they are typically very small. The size of some standardelectrical connectors, including many battery connectors, makes themanufacturing processes for forming large quantities of these smallconnectors extremely difficult to automate. Close tolerances are alsodifficult to maintain during the manufacturing process, and even smallchanges to such a connector can necessitate complete retooling afterconsiderable expenditures in reengineering.

SUMMARY

[0005] The present invention is directed to an electrical connectorincluding a hollow conductive post member with a circular periphery. Thepost member has a foot portion and a distal end. The distal end has agenerally cup shaped indentation. A base member is included having topand bottom surfaces. The foot portion of the post member is mounted tothe top surface. At least one standoff extends from the bottom surfaceof the base member. The at least one standoff is for resting against acontact surface when soldering the electrical connector to the contactsurface, thereby separating the bottom surface from the contact surfaceto define a minimum volume therebetween for occupation by solder.

[0006] In preferred embodiments, the distal end of the post memberincludes an annular ridge encircling the generally cup shapedindentation. The annular ridge has a curved peak. The post memberextends from the top surface of the base member at a right angle. Thegenerally cup shaped indentation includes a generally planar bottom wallhaving an opening therethrough. The opening can form a locking structurecapable of engaging with a locking device of a mating connector. The atleast one standoff includes four standoffs. A solder layer covers thebottom surface of the base member. The base member includes a centralopening therethrough for facilitating spin soldering of the connector.

[0007] The present invention is also directed to an electrical connectorsystem including a male connector having a hollow post member with anopening forming a locking structure. A female connector has a socket forinsertion of the post member of the male connector therein. A lockingdevice is included for extending from the female connector and isengageable with the locking structure opening of the post member of themale connector for locking the female connector to the male connector.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

[0009]FIG. 1 is a side elevational view of a first embodiment of anelectrical connector.

[0010]FIG. 2 is a bottom view of the electrical connector illustrated inFIG. 1.

[0011]FIG. 3 is a top plan view of the electrical connector illustratedin FIG. 1.

[0012]FIG. 4 is a partial cross-sectional view of the electricalconnector illustrated in FIG. 1, taken along lines 4-4 in FIG. 3.

[0013]FIG. 5 is a top view of another embodiment of the presentinvention electrical connector.

[0014]FIG. 6 is a sectional view of the embodiment of FIG. 5.

[0015]FIG. 7 is a bottom view of the embodiment of FIG. 5 with the layerof solder omitted for clarity.

[0016]FIG. 8 is a view of a female connector having a locking devicepositioned for mating with the electrical connector of FIG. 5.

[0017]FIG. 9 is another embodiment of a locking device.

[0018]FIG. 10 is yet another embodiment of a locking device.

[0019]FIG. 11 is still another embodiment of a locking device.

DETAILED DESCRIPTION OF THE INVENTION

[0020]FIG. 1 illustrates an exemplary embodiment of an electricalconnector. Electrical connector 10 includes a post member 12 and a basemember 14, which are connector together to form the connector. Postmember 12 includes a generally cylindrical portion 14 a and a footportion 16 which extends away from the cylindrical portion 14 a.Cylindrical portion 14 a extends upward from foot portion 16, andpreferably angles radially outward between the foot portion 16 and a top18. Top 18 includes a flat peripheral portion 20 adjacent to the outeredge of the top 18, and a concave, cupped inner portion 20. Foot portion16 can be continuous and shaped as a disk (see FIG. 3), or alternativelycan be formed of a plurality of individual tabs which extend away fromcylindrical portion 14 a and which are separated by spaces (notillustrated).

[0021] Base member 14 is generally circular and includes a bottomportion 24 and at least two tabs 26/28 which wrap around foot portion 16of post member 12. A layer of solder 30 is provided on the lower surface32 of bottom portion 24, so that electrical connector 10 can be solderedto a mating surface, as described in greater detail below.

[0022] Referring to FIG. 2, base member 14 is illustrated without solderlayer 30. It is to be understood, however, that preferable embodimentsof electrical connector 10 include solder layer 30. Less preferableembodiments do not include solder layer 30, and are still within thespirit and scope of the invention. FIG. 2 illustrates base member 14having tabs 26/28, which extend into the plane of the illustration. Atleast two notches 34 are formed in base member 14 at the ends of tabs26/28, and are preferably formed with curved ends so that they act torelieve stress concentrations at the ends of the tabs. In the embodimentillustrated in FIG. 2, four notches are provided. Extensions 36/38extend from base member 14 between pairs of notches 34. Extensions 36/38can be eliminated from base member 14, thereby leaving essentially twowider notches on base member 14.

[0023] Lower surface 32 includes at least one, preferably at leastthree, and more preferably four standoffs or posts 40. Standoffs 40extend downwardly away from lower surface 32, up and out of the plane ofthe illustration of FIG. 2. Standoffs 40 are preferably cylindrical, canbe either hollow or solid, and are preferably positioned adjacent to anouter edge 42 of base member 14. Less preferably, standoffs 40 can belocated close to each other and near the center of lower surface 32.

[0024] Turning now to FIG. 3, a top plan view of connector 10 isillustrated. Two tabs 26/28 are illustrated in FIG. 3. According to yetanother embodiment of electrical connector 10, three or more tabs can beprovided on base member 14 which extend around foot portion 16 and whichare spaced apart circumferentially. By way of example and not bylimitation, three tabs can be provided on base member 14 which wraparound foot portion 16. When three tabs are provided, there will bethree gaps 44 (two of which are illustrated in FIG. 3) between the threetabs, and preferably three sets of notches 34. As will be readilyapparent to one of ordinary skill in the art, more than three tabs canbe provided on base member 14 and still be within the spirit and scopeof the invention.

[0025] Tabs 26/28 are generally crescent or “C” shaped, and areseparated by gaps 44. Tabs 26/28 extend radially inward towardcylindrical portion 14 of post member 12. Tabs 26/28 can extend tocylindrical portion 14. When more than two tabs are provided, the tabshave a smaller circumferential length than tabs 26/28, as will bereadily appreciated by one of ordinary skill in the art.

[0026]FIG. 4 illustrates a cross-sectional view of connector 10, withthe upper portions of post member 12 broken away, taken along lines 4-4in FIG. 3. Base member 14 has a top surface 46, which includes dimplesor recesses 48. Recesses 48 are formed in top surface 46 when standoffs40 are formed by stamping base member 14 to deform the base member tocreate the standoffs, and therefore recesses 48 are artifacts of thestamping process. Recesses 48 perform an additional function in basemember 14 by acting as a stress concentrator in the base member.Recesses 48 can therefore assist in assuring that tabs 26/28 wrap aroundfoot portion 16 without causing buckling or binding of base member 14when the tabs are wrapped around the foot portion. When standoffs 40 areformed by a process which does not involve deforming base member 14,recesses 48 can be eliminated, for example, by forming the standoffswith a small rivet or the like.

[0027] Standoffs 40 each have substantially the same height H, measuredfrom their bottom surfaces 50 to lower surface 32, and base member 14has a diameter D defined as the largest linear distance across the lowersurface. Because tabs 26/28 curve up from base member 14, diameter D isslightly smaller than the distance between the edges of tabs 26/28described above with reference to FIG. 2. Height H and diameter Dtherefore together define a minimum volume V below lower surface 32, thevalue of which is computed from the formula:

V=(π/4)·H·D ²

[0028] Thus, for a particular diameter D, and therefore size ofconnector 10, the height H of standoffs 40 determines the volume V.

[0029] Volume V is filled with solder 30, which preferably coversstandoffs 40 so that there is solder in excess of that necessary to fillvolume V. Height H, and therefore volume V of solder 30, is selected sothat electrical connector 10 will bond to a mating surface with apreselected strength, which is a function of the volume V of solderwhich connects the electrical connector to the mating surface. Standoffs40 ensure that no less than volume V of solder 30 is available forjoining connector 10 with a mating surface to which the connector issoldered.

[0030] A process of using electrical connector 10 will now be describedwith reference to FIGS. 1-4. Electrical connector 10, preferably with alayer of solder 30 covering standoffs 40, is placed on a mating surface(not illustrated) so that the layer rests flat against the matingsurface. According to one preferred embodiment of the present invention,the mating surface is a glass surface, e.g., a piece of automobile glassin which an electrical device is embedded, and the glass surfaceincludes an electrically conductive coating, e.g., a silver coating, toform an electrical connection with connector 10. With connector 10resting on the mating surface, a soldering device (not illustrated) ispressed against the connector, e.g., against post portion 12, tabs26/28, or both, with a force F. Because foot portion 16 extends undertabs 26/28 and is connected to post portion 12, force F is transmittedthrough connector 10 in the region above standoffs 40, and through thesolder layer. As will be readily appreciated by one of ordinary skill inthe art, the soldering device also heats solder layer 30 to atemperature at which it becomes liquified. The combined effect of forceF and the liquid state of heated solder layer 30 is to bond theliquified solder to the mating surface and lower surface 32 of basemember 14, including standoffs 40. Standoffs 40, however, prevent forceF from pressing lower surface 32 against the mating surface, andtherefore leaves at least volume V of liquified solder 30 to holdconnector 10 to the mating surface.

[0031] Standoffs 40 also function to maintain base member 14 in agenerally planar shape while force F presses connector 10 against themating surface. By locating standoffs 40 in the area under foot portion16 and tabs 26/28, which is the same area through which force F istransmitted through connector 10, the standoffs transmit all of force F(albeit at a higher pressure) once lower surface 50 has been exposed byliquified solder 32 having flowed away from the standoffs. By requiringall of force F to be transmitted through tabs 26/28, foot portion 16,and standoffs 40 at this stage of the soldering process, the portion ofbase member 14 between the standoffs bears little or no load, andtherefore base member 14 will not be bent by force F. Thus, standoffs 40maintain the planar shape of base member 14 during soldering, whichfurther ensures that connector 10 will be uniformly soldered to themating surface.

[0032] In accordance with a preferred embodiment of connector 10, thediameter of top 18 is about 5.72 mm; the distance between edges 26/28 isabout 8.90 mm; the distance between the lower surface of solder layer 32and the upper surface of tabs 26/28 is about 1.35 mm; the distancebetween the upper surface of tabs 26/28 and top 18 is about 3 mm; thedistance from the center of base member 14 to the center of eachstandoff is about 3.4 mm; each height H is between about 0.05 mm andabout 0.15 mm, preferably about 0.1 mm; post member 12 is formed of70/30 brass of about 0.016 inch thickness; base member 14 is formed of70/30 brass of about 0.012 inch thickness; solder layer 30 is about0.013 inch thick and formed of 25% Sn, 62% Pb, 10% Bi, and 3% Ag, andsolder layer 30 includes a flux coating. Furthermore, post portion 12conforms to the International Electro Technical Commission ISO standardfor battery connectors type 17, miniature non-resilient snap-fastenerconnectors, and the combination of the height H of standoffs 40, theparticular solder chosen, and the effective diameter D of the basemember results in electrical connector 10, when soldered onto asilver-coated windscreen, having a pull-strength of at least about 80pounds.

[0033] Referring to FIGS. 5-7, electrical connector 60 is anotherembodiment of the present invention. Electrical connector 60 is a maleconnector that includes a base member 54 and a post member 52. Basemember 54 is similar to base member 14 of electrical connector 10 butdiffers in that a central opening 64 is formed therethrough tofacilitate the melting of solder 30 during spin soldering. In spinsoldering, electrical connector 60 is held in a chuck and rotated whilepressed against the surface for soldering to until the solder 30 heatsup from friction and melts. Removal of material along the central axis Xof base member 54 removes the area of base member 54 that would havezero rotational velocity during spin soldering and therefore generatelittle or no heat from friction. Base member 54 also has two flats 54 ainstead of the notches 34 and extensions 36/38 of base member 14. Aswith the base member 14, base member 54 includes standoffs 40 having alower surface 50 and a layer of solder 30 on the lower surface 32 ofbottom portion 24. The central opening 64 makes the base member 54 andthe layer of solder 30 generally annular in shape. Furthermore, basemember 34 includes tabs 26/28 for wrapping around the foot portion 16 ofpost member 52 to secure the post member 52 to the base member 54.

[0034] Post member 52 is hollow with a generally circular perimeter orperiphery and an outwardly tapering side wall 53 extending upwardly fromfoot portion 16. Post member 52 also has a distal end 62 which includesan annular ridge 56 having a curved peak 56 a. The annular ridge 56encircles a generally cup shaped indentation 58 which is shown as beinggenerally cylindrical. Indentation 58 has a generally planar horizontalbottom wall 61 with a hole 61 a extending therethrough along centralaxis X into the hollow interior 52 a of post member 52. A cylindricalside wall 63 connects the bottom wall 61 with the annular ridge 56.Although side wall 63 is shown as generally cylindrical, side wall 63may alternatively be generally sloped or curved. The cross section ofpost member 52 through the cup shaped indentation 58 is generallyannular in shape while the cross section of post member 52 through theportion between the indentation 58 and the foot portion 16 is generallycircular in shape. The annular ridge 56 and indentation 58 provide thedistal end 62 with rigidity and strength to prevent crushing thereofduring normal use.

[0035] In one embodiment, base member 54 is 8.6 mm in diameter and flats54 a are 8.2 mm apart. Central opening 62 of base member 54 is about 3mm in diameter. Post member 52 extends 3 mm±0.1 above the tabs 26/28 ofbase member 54. The diameter of post member 52 is 5.72 mm±0.05. Theannular ridge 56 is about 1.8 mm wide and the curved peak 56 a has aradius of about 0.9 mm. The bottom wall 61 of indentation 58 is about1.3 mm below peak 56 a. Indentation 58 has a diameter of about 2.12 mm.The bottom wall 61 and the cylindrical side wall 63 of indentation 58are joined together by a radius of about 0.38 mm. Hole 61 a in bottomwall 61 is about 1.8 mm in diameter. Electrical connector 60 is made of70/30 brass with base 54 being 0.012±0.001 inches (0.3±0.025 mm) thickand post member 52 being 0.016±0.001 inches (0.4±0.025 mm) thick. Solderlayer 30 is similar to that in electrical connector 10. The base member54 and post member 52 are preferably formed by separate dies andassembled together by a third die.

[0036] Referring to FIG. 8, electrical connector 60 is typically engagedwith a socket 66 of a female electrical connector 70. Arrows A indicatethat connectors 60/70 are engageable and disengageable from each other.Socket 66 can be any one of a number of different female sockets and isschematically shown as being generally cup shaped with an interior 66 a.When post member 52 of electrical connector 60 is engaged withininterior 66 a of the socket 66 of female electrical connector 70, postmember 52 comes in electrical contact with socket 66 in a manner similarto that when electrical connector 10 is engaged therein. The femaleelectrical connector 70 can optionally include a locking device 68 forlocking the electrical connectors 60/70 together.

[0037] In the embodiment shown in FIG. 8, locking device 68 includes abutton 72 having two or more resilient prongs 74 extending into theinterior 66 a of socket 66 through an opening 67 in socket 66. Prongs 74have outwardly directed locking protrusions 74 a, and tips 74 b whichinwardly angle forwardly towards each other. Locking device 68 isoperable in the direction of arrows B. To lock electrical connector 60within socket 66, the user pushes button 72 towards socket 66 whichmoves the angled tips 74 b of prongs 74 further into the interior 66 aof socket 66 and into the hole 61 a within the post member 52 ofelectrical connector 60. The angled tips 74 b engage the hole 61 a, andas the tips 74 b progress therethrough, the angled surfaces of the tips74 b bend prongs 74 inwardly and force the tips 74 b towards each other.Bending the prongs 74 inwardly brings the locking protrusions 74 acloser together allowing them to pass through hole 61 a. Once lockingprotrusions 74 a reach the interior 52 a of the post member 52 ofelectrical connector 60, the locking protrusions 74 a engage the bottomwall 61 of indentation 58, thereby trapping or capturing bottom wall 61to provide locking thereof and preventing easy removal of post member 52from socket 66. In this manner, the bottom wall 61, and the hole oropening 61 a therethrough, form a locking structure. Locking device 68may be disengaged from post member 52 by pulling on button 72 to pullprongs 74 from the hole 61 a in post member 52.

[0038] Referring to FIG. 9, locking device 73 is another embodiment of alocking device which differs from locking device 68 in that prongs 75have rearwardly and outwardly angled portions 75 a terminating in tips75 b. The tips 75 b, when engaged with post member 52, trap or capturebottom wall 61.

[0039] Referring to FIG. 10, locking device 74 is yet another embodimentof a locking device which includes a protrusion 76 for engaging hole 61a within the indentation 58 of post member 52. Protrusion 76 has aspring loaded ball 76 a for trapping bottom wall 61. Although lockingdevices 68, 73 and 74 have been shown to be movably engageble relativeto socket 66, alternatively, the locking portions of locking devices 68,73 and 74 can be incorporated as part of the socket 66 to lock the postmember 52 of electrical connector 60 with female connector 70 instantlyupon engagement.

[0040] Referring to FIG. 11, locking device 80 is still anotherembodiment of a locking device which includes a knob 78 for turning athreaded locking screw 82. The threaded locking screw 82 engages thehole 61 a within the indentation 58 of post member 52 for locking theelectrical connector 60 within the socket 66 of female connector 70.Locking screw 82 has a tapered tip 82 a which facilitates engagementwith hole 61 a.

[0041] While this invention has been particularly shown and describedwith references to preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the scope of the inventionencompassed by the appended claims. For example, features of thedifferent embodiments described above can be combined or omitted. Inaddition, although particular materials and dimensions have beendescribed above, it is understood that such parameters can be varieddepending upon the application at hand. Furthermore, although thepresent invention has been described in a particular orientation withparticular directional terminology, it is understood that the connectorscan be oriented in any direction since the orientation of the connectorsis dependent upon the application at hand.

What is claimed is:
 1. An electrical connector comprising: a hollowgenerally cylindrical post formed from electrically conductive sheetmaterial for engaging a mating connector, the post including a tophaving a top surface, a generally planar base member extending radiallyoutward from the post, the base member having a generally circulardiameter; and at least one standoff located on a bottom surface of thebase member for defining a minimum volume of solder below the bottomsurface during soldering.
 2. The connector of claim 1 in which the topsurface includes a concave portion.
 3. The connector of claim 1 furthercomprising a layer of solder located on the bottom surface of the basemember for soldering the electrical connector to a surface.
 4. Theconnector of claim 3 in which the layer of solder has a thicknessgreater than a height of said at least one standoff.
 5. The connector ofclaim 3 in which the base member includes a central opening.
 6. Theconnector of claim 5 in which the layer of solder is generally annularin shape.
 7. An electrical connector comprising: a hollow generallycylindrical post formed from electrically conductive sheet material forengaging a mating connector, the post including a generally planar diskshaped foot portion extending radially outward from the post; and atleast one standoff located below the foot portion for defining a minimumvolume of solder during soldering.
 8. The connector of claim 7 furthercomprising a layer of solder located below the foot portion forsoldering the electrical connector to a surface.
 9. A method of formingan electrical connector comprising: forming from electrically conductivesheet material, a hollow generally cylindrical post for engaging amating connector, the post including a top having a top surface; forminga generally planar base member extending radially outward from the post,the base member having a generally circular diameter; and forming atleast one standoff located on a bottom surface of the base member fordefining a minimum volume of solder below the bottom surface duringsoldering.
 10. The method of claim 9 further comprising forming the topsurface with a concave portion.
 11. The method of claim 9 furthercomprising forming a layer of solder located on the bottom surface ofthe base member for soldering the electrical connector to a surface. 12.The method of claim 11 further comprising forming the layer of solderwith a thickness that is greater than a height of said at least onestandoff.
 13. The method of claim 11 further comprising forming acentral opening through the base member.
 14. The method of claim 13further comprising forming a layer of solder that is generally annularin shape.
 15. A method of forming an electrical connector comprising:forming from electrically conductive sheet material, a hollow generallycylindrical post for engaging a mating connector, the post including agenerally planar disk shaped foot portion extending radially outwardfrom the post; and locating at least one standoff below the foot portionfor defining a minimum volume of solder during soldering.
 16. The methodof claim 15 further comprising forming a layer of solder located belowthe foot portion for soldering the electrical connector to a surface.17. A method of soldering an electrical connector comprising: providingthe electrical connector with a hollow generally cylindrical post formedfrom electrically conductive sheet material for engaging a matingconnector, the post including a top having a top surface, a generallyplanar base member extending radially outward from the post, the basemember having a generally circular diameter; and defining a minimumvolume of solder below a bottom surface of the base member duringsoldering of the electrical connector to a surface with at least onestandoff located on the bottom surface of the base member.